#outBox {
  width: 1003px;
  height: 1201px;
  margin: 50px auto;
  display: flex;
  flex-wrap: wrap;
}
.inBox {
  width: 250px;
  height: 250px;
  text-align: center;
  line-height: 250px;
  font-size: 120px;
}
.inBox:nth-child(-n + 12) {
  border-bottom: 1px solid black;
}
.inBox:nth-child(4n) {
  border-left: 1px solid black;
}
.inBox:nth-child(4n-1) {
  border-left: 1px solid black;
}
.inBox:nth-child(4n-2) {
  border-left: 1px solid black;
}
#bottomBox {
  width: 750px;
  height: 200px;
  display: flex;
  justify-content: space-between;
  line-height: 100px;
  font-size: 30px;
}